This invention relates to acoustic surface wave devices. More particularly, it is concerned with acoustic surface wave devices including a three-phase unidirectional transducer.
Three-phase acoustic surface wave transducers which propagate acoustic waves along the surface of a propagating medium in only one direction have been developed. These unidirectional transducers employ three sets of electrodes. A single phase source of electrical signals is coupled to the three sets of electrodes through impedance-matching and phase-shifting networks so that the three sets of electrodes are activated in the proper phase relationships to generate acoustic surface waves which propagate in one direction only. With three-phase unidirectional transducers heretofore available complicated networks for impedance-matching and phase-shifting have been required thus limiting the applications in which the devices may be economically employed.